Aquanauts Living on Ocean Floor Prepare to Surface

From the cramped conditions inside a school-bus-sized metal tube at the
bottom of the ocean, scientist Chris Finelli traded his scuba gear for a T-shirt and bare feet, ready to talk about his latest
mission: monitoring sponges on Conch Reef, more than three miles off the
coast of Florida.

Sponges, bottom-dwelling filter-feeders, are one of two players
locked in a silent battle for supremacy that is taking place at these
coral reefs and others across the globe.

As coral populations disappear
— they're down by 90 percent around Florida — other species are
fighting for the newly freed up ocean real estate. The two top
contenders to take over are sponges and algae, and which one emerges
victorious will have far-reaching consequences for the species that make
their homes in coral reefs and for the humans that depend on them.

In the face of such serious subject matter, Finelli still worried he
sounded a bit like Donald Duck, explaining that at 50 feet (15 meters)
below the ocean's surface, the extreme pressure can make people sound
like they've sucked in a hit of helium.

"You get used to hearing yourself in a funny voice when you're down
here," said the University of North Carolina Wilmington associate
professor.

Finelli, along with several UNCW grad students and technicians, has
been living deep under water for nine days now, aboard the Aquarius, the
only seafloor laboratory and habitat in the world. The National Oceanic
and Atmospheric Administration (NOAA) owns the facility, which is run
by UNCW.

Ocean researchers can conduct much longer dives
from the Aquarius than are possible from a boat, and UNCW has been
taking advantage of this since 1997, when this sponge study first got
under way.

The research is partly focused on giant barrel sponges, which were
recently revealed to be among the oldest living organisms on the planet.
The largest of the species can grow up to 20 feet (6 meters) across and
live up to 2,000 years.

Although the barrel sponges found on Conch Reef aren't quite that
enormous, all sponges play an important role in maintaining water
quality. Sponges filter about 100 times their own volume every hour,
cleaning the ocean and moving nutrients through the ecosystem. They also
provide a home for creatures in a way that is somewhat similar to coral
reefs.

Algae and seaweed don't do any of those things though, said Joseph
Pawlik, a UNCW professor, speaking from his office. If these plants win
the ocean-bottom war, it could destroy valuable habitat.

"If you can't have corals, better that you should have sponges,
rather than macroalgae," Pawlik said. And right now it looks like
sponges in the area are winning out over algae and seaweed, he said.
Over the last six years, he added, Florida has seen barrel sponges
increase by 40 percent.

Finelli's findings seem to support this increase. The team discovered
a huge number of young sponges within the 50-foot (16-meter) -diameter
study area, something Finelli said was a nice surprise.

However, despite the marked increase in baby sponges the team found,
Pawlik said, it's not clear whether the total amount of sponge biomass
is increasing or decreasing.

"The interesting thing is we've also seen diseases take out some of
the largest individuals on the reef," Pawlik said, so whether or not the
sheer amount of sponge tissue in the oceans is increasing isn't known.

Finelli and his team will began the 16-hour decompression process on Wendesday of this week, and will swim to the surface on Thursday. After spending nine hours each
day on dives, the team will need time for their lungs to adjust to life
back on dry land.